Origin to geometry by default
I took the python template Simple Operator and inserted the operator that sets the origin to geometry (found when pressing the button and looking in the Info window). I then selected a few objects and set them up with origins at the cursor so I could test, and ran the script. With all of them selected, I pressed the space bar and chose "Origin to Geometry All", the name of the new operator.

Maybe it could help, though it isn't as clean as it could be with some work.

edit: turns out you don't need all that since the operator works on multiple objects at once already. Simply select all the objects you need to change origins to geometry and then press 'Origin to Geometry' in the tool bar. So if you have imported 30 objects and need to fix their origins, select all and then press the operator.